OffscreenCanvas.convertToBlob() - Web APIs 编辑

Experimental

This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The OffscreenCanvas.convertToBlob()method creates a Blob object representing the image contained in the canvas.

Syntax

Promise<Blob> OffscreenCanvas.convertToBlob(options);

Parameters

optionsOptional

You can specify several options when converting your OffscreenCanvas object into a Blob object, for example:

const blob = offscreenCanvas.convertToBlob({
  type: "image/jpeg",
  quality: 0.95
});

options:

• type: A DOMString indicating the image format. The default type is image/png.
• quality: A Number between 0 and 1 indicating image quality if the type option is image/jpeg or image/webp. If this argument is anything else, the default value for image quality is used. Other arguments are ignored.

Return value

A Promise returning a Blob object representing the image contained in the canvas.

Examples

var offscreen = new OffscreenCanvas(256, 256);
var gl = offscreen.getContext("webgl");

// ... some drawing using the gl context ...

offscreen.convertToBlob().then(function(blob) {
  console.log(blob);
});

// Blob { size: 334, type: "image/png" }

Specifications

Browser compatibility

BCD tables only load in the browser

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-dataand send us a pull request.

See also

• The interface defining this method, OffscreenCanvas.